15 files changed, 188 insertions, 72 deletions

diff --git a/src/corelib/global/global.pri b/src/corelib/global/global.pri
index a878a83bcb..2b4fd6d661 100644
--- a/src/corelib/global/global.pri
+++ b/src/corelib/global/global.pri
@@ -63,7 +63,10 @@ unset(f16c_cxx)
 VERSIONTAGGING_SOURCES = global/qversiontagging.cpp
 
 darwin: SOURCES += global/qoperatingsystemversion_darwin.mm
-win32: SOURCES += global/qoperatingsystemversion_win.cpp
+win32 {
+    SOURCES += global/qoperatingsystemversion_win.cpp
+    HEADERS += global/qoperatingsystemversion_win_p.h
+}
 
 # qlibraryinfo.cpp includes qconfig.cpp
 INCLUDEPATH += $$QT_BUILD_TREE/src/corelib/global
diff --git a/src/corelib/global/minimum-linux_p.h b/src/corelib/global/minimum-linux_p.h
index 324744b856..bad2488b4d 100644
--- a/src/corelib/global/minimum-linux_p.h
+++ b/src/corelib/global/minimum-linux_p.h
@@ -67,7 +67,7 @@ QT_BEGIN_NAMESPACE
  * - inotify_init1              before 2.6.12-rc12
  * - futex(2)                   before 2.6.12-rc12
  * - FUTEX_WAKE_OP              2.6.14                  FUTEX_OP
- * - linkat(2)                  2.6.17                  O_TMPFILE
+ * - linkat(2)                  2.6.17                  O_TMPFILE && QT_CONFIG(linkat)
  * - FUTEX_PRIVATE_FLAG         2.6.22
  * - O_CLOEXEC                  2.6.23
  * - eventfd                    2.6.23
diff --git a/src/corelib/global/qconfig-bootstrapped.h b/src/corelib/global/qconfig-bootstrapped.h
index eb56d2d0cd..0df593941d 100644
--- a/src/corelib/global/qconfig-bootstrapped.h
+++ b/src/corelib/global/qconfig-bootstrapped.h
@@ -87,6 +87,11 @@
 #define QT_FEATURE_futimens -1
 #define QT_FEATURE_futimes -1
 #define QT_FEATURE_library -1
+#ifdef __linux__
+# define QT_FEATURE_linkat 1
+#else
+# define QT_FEATURE_linkat -1
+#endif
 #define QT_NO_QOBJECT
 #define QT_FEATURE_process -1
 #define QT_FEATURE_regularexpression -1
diff --git a/src/corelib/global/qfloat16.cpp b/src/corelib/global/qfloat16.cpp
index 129ab4ded2..3046a47292 100644
--- a/src/corelib/global/qfloat16.cpp
+++ b/src/corelib/global/qfloat16.cpp
@@ -129,8 +129,8 @@ extern "C" {
 #  define f16cextern    extern
 #endif
 
-f16cextern void qFloatToFloat16_fast(quint16 *out, const float *in, qssize_t len) Q_DECL_NOTHROW;
-f16cextern void qFloatFromFloat16_fast(float *out, const quint16 *in, qssize_t len) Q_DECL_NOTHROW;
+f16cextern void qFloatToFloat16_fast(quint16 *out, const float *in, qsizetype len) Q_DECL_NOTHROW;
+f16cextern void qFloatFromFloat16_fast(float *out, const quint16 *in, qsizetype len) Q_DECL_NOTHROW;
 
 #undef f16cextern
 }
@@ -141,20 +141,20 @@ static inline bool hasFastF16()
     return true;
 }
 
-static void qFloatToFloat16_fast(quint16 *out, const float *in, qssize_t len) Q_DECL_NOTHROW
+static void qFloatToFloat16_fast(quint16 *out, const float *in, qsizetype len) Q_DECL_NOTHROW
 {
     __fp16 *out_f16 = reinterpret_cast<__fp16 *>(out);
-    qssize_t i = 0;
+    qsizetype i = 0;
     for (; i < len - 3; i += 4)
         vst1_f16(out_f16 + i, vcvt_f16_f32(vld1q_f32(in + i)));
     SIMD_EPILOGUE(i, len, 3)
         out_f16[i] = __fp16(in[i]);
 }
 
-static void qFloatFromFloat16_fast(float *out, const quint16 *in, qssize_t len) Q_DECL_NOTHROW
+static void qFloatFromFloat16_fast(float *out, const quint16 *in, qsizetype len) Q_DECL_NOTHROW
 {
     const __fp16 *in_f16 = reinterpret_cast<const __fp16 *>(in);
-    qssize_t i = 0;
+    qsizetype i = 0;
     for (; i < len - 3; i += 4)
         vst1q_f32(out + i, vcvt_f32_f16(vld1_f16(in_f16 + i)));
     SIMD_EPILOGUE(i, len, 3)
@@ -166,12 +166,12 @@ static inline bool hasFastF16()
     return false;
 }
 
-static void qFloatToFloat16_fast(quint16 *, const float *, qssize_t) Q_DECL_NOTHROW
+static void qFloatToFloat16_fast(quint16 *, const float *, qsizetype) Q_DECL_NOTHROW
 {
     Q_UNREACHABLE();
 }
 
-static void qFloatFromFloat16_fast(float *, const quint16 *, qssize_t) Q_DECL_NOTHROW
+static void qFloatFromFloat16_fast(float *, const quint16 *, qsizetype) Q_DECL_NOTHROW
 {
     Q_UNREACHABLE();
 }
@@ -182,12 +182,12 @@ static void qFloatFromFloat16_fast(float *, const quint16 *, qssize_t) Q_DECL_NO
     Converts \a len floats from \a in to qfloat16 and stores them in \a out.
     Both \a in and \a out must have \a len allocated entries.
 */
-Q_CORE_EXPORT void qFloatToFloat16(qfloat16 *out, const float *in, qssize_t len) Q_DECL_NOTHROW
+Q_CORE_EXPORT void qFloatToFloat16(qfloat16 *out, const float *in, qsizetype len) Q_DECL_NOTHROW
 {
     if (hasFastF16())
         return qFloatToFloat16_fast(reinterpret_cast<quint16 *>(out), in, len);
 
-    for (qssize_t i = 0; i < len; ++i)
+    for (qsizetype i = 0; i < len; ++i)
         out[i] = qfloat16(in[i]);
 }
 
@@ -197,12 +197,12 @@ Q_CORE_EXPORT void qFloatToFloat16(qfloat16 *out, const float *in, qssize_t len)
     Converts \a len qfloat16 from \a in to floats and stores them in \a out.
     Both \a in and \a out must have \a len allocated entries.
 */
-Q_CORE_EXPORT void qFloatFromFloat16(float *out, const qfloat16 *in, qssize_t len) Q_DECL_NOTHROW
+Q_CORE_EXPORT void qFloatFromFloat16(float *out, const qfloat16 *in, qsizetype len) Q_DECL_NOTHROW
 {
     if (hasFastF16())
         return qFloatFromFloat16_fast(out, reinterpret_cast<const quint16 *>(in), len);
 
-    for (qssize_t i = 0; i < len; ++i)
+    for (qsizetype i = 0; i < len; ++i)
         out[i] = float(in[i]);
 }
 
diff --git a/src/corelib/global/qfloat16.h b/src/corelib/global/qfloat16.h
index bf223bee0c..a8befd7adb 100644
--- a/src/corelib/global/qfloat16.h
+++ b/src/corelib/global/qfloat16.h
@@ -88,8 +88,8 @@ private:
 
 Q_DECLARE_TYPEINFO(qfloat16, Q_PRIMITIVE_TYPE);
 
-Q_CORE_EXPORT void qFloatToFloat16(qfloat16 *, const float *, qssize_t length) Q_DECL_NOTHROW;
-Q_CORE_EXPORT void qFloatFromFloat16(float *, const qfloat16 *, qssize_t length) Q_DECL_NOTHROW;
+Q_CORE_EXPORT void qFloatToFloat16(qfloat16 *, const float *, qsizetype length) Q_DECL_NOTHROW;
+Q_CORE_EXPORT void qFloatFromFloat16(float *, const qfloat16 *, qsizetype length) Q_DECL_NOTHROW;
 
 Q_REQUIRED_RESULT Q_CORE_EXPORT bool qIsInf(qfloat16 f) Q_DECL_NOTHROW;    // complements qnumeric.h
 Q_REQUIRED_RESULT Q_CORE_EXPORT bool qIsNaN(qfloat16 f) Q_DECL_NOTHROW;    // complements qnumeric.h
diff --git a/src/corelib/global/qfloat16_f16c.c b/src/corelib/global/qfloat16_f16c.c
index c88dbb6944..31dff0b154 100644
--- a/src/corelib/global/qfloat16_f16c.c
+++ b/src/corelib/global/qfloat16_f16c.c
@@ -54,9 +54,9 @@ extern "C" {
 #endif
 
 QT_FUNCTION_TARGET(F16C)
-void qFloatToFloat16_fast(quint16 *out, const float *in, qssize_t len) Q_DECL_NOTHROW
+void qFloatToFloat16_fast(quint16 *out, const float *in, qsizetype len) Q_DECL_NOTHROW
 {
-    qssize_t i = 0;
+    qsizetype i = 0;
     for (; i < len - 7; i += 8)
         _mm_storeu_si128((__m128i *)(out + i), _mm256_cvtps_ph(_mm256_loadu_ps(in + i), 0));
     if (i < len - 3) {
@@ -69,9 +69,9 @@ void qFloatToFloat16_fast(quint16 *out, const float *in, qssize_t len) Q_DECL_NO
 }
 
 QT_FUNCTION_TARGET(F16C)
-void qFloatFromFloat16_fast(float *out, const quint16 *in, qssize_t len) Q_DECL_NOTHROW
+void qFloatFromFloat16_fast(float *out, const quint16 *in, qsizetype len) Q_DECL_NOTHROW
 {
-    qssize_t i = 0;
+    qsizetype i = 0;
     for (; i < len - 7; i += 8)
         _mm256_storeu_ps(out + i, _mm256_cvtph_ps(_mm_loadu_si128((const __m128i *)(in + i))));
     if (i < len - 3) {
diff --git a/src/corelib/global/qfloat16_p.h b/src/corelib/global/qfloat16_p.h
index ae52e64435..f3fc96e119 100644
--- a/src/corelib/global/qfloat16_p.h
+++ b/src/corelib/global/qfloat16_p.h
@@ -61,9 +61,9 @@ static inline bool qt_is_inf(qfloat16 d) Q_DECL_NOTHROW
     bool is_inf;
     uchar *ch = (uchar *)&d;
     if (QSysInfo::ByteOrder == QSysInfo::BigEndian)
-        is_inf = (ch[0] & 0x7c) == 0x7c;
+        is_inf = (ch[0] & 0x7c) == 0x7c && (ch[0] & 0x02) == 0;
     else
-        is_inf = (ch[1] & 0x7c) == 0x7c;
+        is_inf = (ch[1] & 0x7c) == 0x7c && (ch[1] & 0x02) == 0;
     return is_inf;
 }
 
diff --git a/src/corelib/global/qglobal.cpp b/src/corelib/global/qglobal.cpp
index c3b074c59f..a8fa7654ba 100644
--- a/src/corelib/global/qglobal.cpp
+++ b/src/corelib/global/qglobal.cpp
@@ -46,6 +46,9 @@
 #include "qdatetime.h"
 #include "qoperatingsystemversion.h"
 #include "qoperatingsystemversion_p.h"
+#if defined(Q_OS_WIN) || defined(Q_OS_CYGWIN) || defined(Q_OS_WINRT)
+#include "qoperatingsystemversion_win_p.h"
+#endif
 #include <private/qlocale_tools_p.h>
 
 #include <qmutex.h>
@@ -164,8 +167,8 @@ Q_STATIC_ASSERT_X(std::numeric_limits<float>::radix == 2,
 
 // not required by the definition of size_t, but we depend on this
 Q_STATIC_ASSERT_X(sizeof(size_t) == sizeof(void *), "size_t and a pointer don't have the same size");
-Q_STATIC_ASSERT(sizeof(size_t) == sizeof(qssize_t)); // implied by the definition
-Q_STATIC_ASSERT((std::is_same<qssize_t, qptrdiff>::value));
+Q_STATIC_ASSERT(sizeof(size_t) == sizeof(qsizetype)); // implied by the definition
+Q_STATIC_ASSERT((std::is_same<qsizetype, qptrdiff>::value));
 
 /*!
     \class QFlag
@@ -827,7 +830,7 @@ Q_STATIC_ASSERT((std::is_same<qssize_t, qptrdiff>::value));
 */
 
 /*!
-    \typedef qssize_t
+    \typedef qsizetype
     \relates <QtGlobal>
     \since 5.10
 
@@ -836,7 +839,7 @@ Q_STATIC_ASSERT((std::is_same<qssize_t, qptrdiff>::value));
     This type is guaranteed to be the same size as a \c size_t on all
     platforms supported by Qt.
 
-    Note that qssize_t is signed. Use \c size_t for unsigned values.
+    Note that qsizetype is signed. Use \c size_t for unsigned values.
 
     \sa qptrdiff
 */
diff --git a/src/corelib/global/qglobal.h b/src/corelib/global/qglobal.h
index d439085dbc..7873ab2b43 100644
--- a/src/corelib/global/qglobal.h
+++ b/src/corelib/global/qglobal.h
@@ -250,7 +250,7 @@ typedef quint64 qulonglong;
 // In C++ mode, we define below using QIntegerForSize template
 Q_STATIC_ASSERT_X(sizeof(ptrdiff_t) == sizeof(size_t), "Weird ptrdiff_t and size_t definitions");
 typedef ptrdiff_t qptrdiff;
-typedef ptrdiff_t qssize_t;
+typedef ptrdiff_t qsizetype;
 typedef ptrdiff_t qintptr;
 typedef size_t quintptr;
 #endif
@@ -475,7 +475,7 @@ namespace QtPrivate {
       sizeof(void *) == sizeof(quintptr)
       && sizeof(void *) == sizeof(qptrdiff)
 
-  size_t and qssize_t are not guaranteed to be the same size as a pointer, but
+  size_t and qsizetype are not guaranteed to be the same size as a pointer, but
   they usually are.
 */
 template <int> struct QIntegerForSize;
@@ -492,7 +492,7 @@ typedef QIntegerForSize<Q_PROCESSOR_WORDSIZE>::Unsigned qregisteruint;
 typedef QIntegerForSizeof<void*>::Unsigned quintptr;
 typedef QIntegerForSizeof<void*>::Signed qptrdiff;
 typedef qptrdiff qintptr;
-using qssize_t = QIntegerForSizeof<std::size_t>::Signed;
+using qsizetype = QIntegerForSizeof<std::size_t>::Signed;
 
 /* moc compats (signals/slots) */
 #ifndef QT_MOC_COMPAT
diff --git a/src/corelib/global/qlogging.cpp b/src/corelib/global/qlogging.cpp
index 6602d53b08..0861763492 100644
--- a/src/corelib/global/qlogging.cpp
+++ b/src/corelib/global/qlogging.cpp
@@ -61,7 +61,10 @@
 #include <qt_windows.h>
 #endif
 #if QT_CONFIG(slog2)
-#include <slog2.h>
+#include <sys/slog2.h>
+#endif
+#if QT_HAS_INCLUDE(<paths.h>)
+#include <paths.h>
 #endif
 
 #ifdef Q_OS_ANDROID
@@ -215,8 +218,11 @@ static bool willLogToConsole()
 #  ifdef Q_OS_WIN
     return GetConsoleWindow();
 #  elif defined(Q_OS_UNIX)
+#    ifndef _PATH_TTY
+#    define _PATH_TTY "/dev/tty"
+#    endif
     // if /dev/tty exists, we can only open it if we have a controlling TTY
-    int devtty = qt_safe_open("/dev/tty", O_RDONLY);
+    int devtty = qt_safe_open(_PATH_TTY, O_RDONLY);
     if (devtty == -1 && (errno == ENOENT || errno == EPERM || errno == ENXIO)) {
         // no /dev/tty, fall back to isatty on stderr
         return isatty(STDERR_FILENO);
diff --git a/src/corelib/global/qnamespace.h b/src/corelib/global/qnamespace.h
index 38f194afb5..2773992b47 100644
--- a/src/corelib/global/qnamespace.h
+++ b/src/corelib/global/qnamespace.h
@@ -477,6 +477,8 @@ public:
 
         WA_TabletTracking = 129,
 
+        WA_ContentsMarginsRespectsSafeArea = 130,
+
         // Add new attributes before this line
         WA_AttributeCount
     };
diff --git a/src/corelib/global/qoperatingsystemversion_win.cpp b/src/corelib/global/qoperatingsystemversion_win.cpp
index 060ca2f7da..f3662ae1f9 100644
--- a/src/corelib/global/qoperatingsystemversion_win.cpp
+++ b/src/corelib/global/qoperatingsystemversion_win.cpp
@@ -37,7 +37,10 @@
 **
 ****************************************************************************/
 
+#include "qoperatingsystemversion_win_p.h"
+
 #include "qoperatingsystemversion_p.h"
+
 #include <qt_windows.h>
 #include <qbytearray.h>
 
diff --git a/src/corelib/global/qoperatingsystemversion_win_p.h b/src/corelib/global/qoperatingsystemversion_win_p.h
new file mode 100644
index 0000000000..446bd286fc
--- /dev/null
+++ b/src/corelib/global/qoperatingsystemversion_win_p.h
@@ -0,0 +1,63 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QOPERATINGSYSTEMVERSION_WIN_P_H
+#define QOPERATINGSYSTEMVERSION_WIN_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API. It exists purely as an
+// implementation detail. This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtCore/qglobal.h>
+#include <qt_windows.h>
+
+QT_BEGIN_NAMESPACE
+
+OSVERSIONINFOEX qWindowsVersionInfo();
+
+QT_END_NAMESPACE
+
+#endif // QOPERATINGSYSTEMVERSION_WIN_P_H
diff --git a/src/corelib/global/qrandom.cpp b/src/corelib/global/qrandom.cpp
index 7da86188bb..f5c01aeaa6 100644
--- a/src/corelib/global/qrandom.cpp
+++ b/src/corelib/global/qrandom.cpp
@@ -93,7 +93,7 @@ DECLSPEC_IMPORT BOOLEAN WINAPI SystemFunction036(PVOID RandomBuffer, ULONG Rando
 QT_BEGIN_NAMESPACE
 
 #if defined(Q_PROCESSOR_X86) && QT_COMPILER_SUPPORTS_HERE(RDRND)
-static qssize_t qt_random_cpu(void *buffer, qssize_t count) Q_DECL_NOTHROW;
+static qsizetype qt_random_cpu(void *buffer, qsizetype count) Q_DECL_NOTHROW;
 
 #  ifdef Q_PROCESSOR_X86_64
 #    define _rdrandXX_step _rdrand64_step
@@ -101,7 +101,7 @@ static qssize_t qt_random_cpu(void *buffer, qssize_t count) Q_DECL_NOTHROW;
 #    define _rdrandXX_step _rdrand32_step
 #  endif
 
-static QT_FUNCTION_TARGET(RDRND) qssize_t qt_random_cpu(void *buffer, qssize_t count) Q_DECL_NOTHROW
+static QT_FUNCTION_TARGET(RDRND) qsizetype qt_random_cpu(void *buffer, qsizetype count) Q_DECL_NOTHROW
 {
     unsigned *ptr = reinterpret_cast<unsigned *>(buffer);
     unsigned *end = ptr + count;
@@ -122,7 +122,7 @@ out:
     return ptr - reinterpret_cast<unsigned *>(buffer);
 }
 #else
-static qssize_t qt_random_cpu(void *, qssize_t)
+static qsizetype qt_random_cpu(void *, qsizetype)
 {
     return 0;
 }
@@ -136,10 +136,10 @@ enum {
 struct QRandomGenerator::SystemGenerator
 {
 #if QT_CONFIG(getentropy)
-    static qssize_t fillBuffer(void *buffer, qssize_t count) Q_DECL_NOTHROW
+    static qsizetype fillBuffer(void *buffer, qsizetype count) Q_DECL_NOTHROW
     {
         // getentropy can read at most 256 bytes, so break the reading
-        qssize_t read = 0;
+        qsizetype read = 0;
         while (count - read > 256) {
             // getentropy can't fail under normal circumstances
             int ret = getentropy(reinterpret_cast<uchar *>(buffer) + read, 256);
@@ -195,24 +195,24 @@ struct QRandomGenerator::SystemGenerator
 
     Q_DECL_CONSTEXPR SystemGenerator() : fdp1 Q_BASIC_ATOMIC_INITIALIZER(0) {}
 
-    qssize_t fillBuffer(void *buffer, qssize_t count)
+    qsizetype fillBuffer(void *buffer, qsizetype count)
     {
         int fd = openDevice();
         if (Q_UNLIKELY(fd < 0))
             return 0;
 
         qint64 n = qt_safe_read(fd, buffer, count);
-        return qMax<qssize_t>(n, 0);        // ignore any errors
+        return qMax<qsizetype>(n, 0);        // ignore any errors
     }
 
 #elif defined(Q_OS_WIN) && !defined(Q_OS_WINRT)
-    qssize_t fillBuffer(void *buffer, qssize_t count) Q_DECL_NOTHROW
+    qsizetype fillBuffer(void *buffer, qsizetype count) Q_DECL_NOTHROW
     {
         auto RtlGenRandom = SystemFunction036;
         return RtlGenRandom(buffer, ULONG(count)) ? count: 0;
     }
 #elif defined(Q_OS_WINRT)
-    qssize_t fillBuffer(void *, qssize_t) Q_DECL_NOTHROW
+    qsizetype fillBuffer(void *, qsizetype) Q_DECL_NOTHROW
     {
         // always use the fallback
         return 0;
@@ -243,7 +243,7 @@ struct QRandomGenerator::SystemGenerator
 
 #if defined(Q_OS_WIN)
 static void fallback_update_seed(unsigned) {}
-static void fallback_fill(quint32 *ptr, qssize_t left) Q_DECL_NOTHROW
+static void fallback_fill(quint32 *ptr, qsizetype left) Q_DECL_NOTHROW
 {
     // on Windows, rand_s is a high-quality random number generator
     // and it requires no seeding
@@ -255,14 +255,14 @@ static void fallback_fill(quint32 *ptr, qssize_t left) Q_DECL_NOTHROW
 }
 #elif QT_CONFIG(getentropy)
 static void fallback_update_seed(unsigned) {}
-static void fallback_fill(quint32 *, qssize_t) Q_DECL_NOTHROW
+static void fallback_fill(quint32 *, qsizetype) Q_DECL_NOTHROW
 {
     // no fallback necessary, getentropy cannot fail under normal circumstances
     Q_UNREACHABLE();
 }
 #elif defined(Q_OS_BSD4)
 static void fallback_update_seed(unsigned) {}
-static void fallback_fill(quint32 *ptr, qssize_t left) Q_DECL_NOTHROW
+static void fallback_fill(quint32 *ptr, qsizetype left) Q_DECL_NOTHROW
 {
     // BSDs have arc4random(4) and these work even in chroot(2)
     arc4random_buf(ptr, left * sizeof(*ptr));
@@ -281,7 +281,7 @@ Q_NEVER_INLINE
 #ifdef Q_CC_GNU
 __attribute__((cold))   // this function is pretty big, so optimize for size
 #endif
-static void fallback_fill(quint32 *ptr, qssize_t left) Q_DECL_NOTHROW
+static void fallback_fill(quint32 *ptr, qsizetype left) Q_DECL_NOTHROW
 {
     quint32 scratch[12];    // see element count below
     quint32 *end = scratch;
@@ -358,7 +358,7 @@ Q_NEVER_INLINE void QRandomGenerator::SystemGenerator::generate(quint32 *begin,
     Q_DECL_NOEXCEPT_EXPR(FillBufferNoexcept)
 {
     quint32 *buffer = begin;
-    qssize_t count = end - begin;
+    qsizetype count = end - begin;
 
     if (Q_UNLIKELY(uint(qt_randomdevice_control) & SetRandomData)) {
         uint value = uint(qt_randomdevice_control) & RandomDataMask;
@@ -366,14 +366,14 @@ Q_NEVER_INLINE void QRandomGenerator::SystemGenerator::generate(quint32 *begin,
         return;
     }
 
-    qssize_t filled = 0;
+    qsizetype filled = 0;
     if (qt_has_hwrng() && (uint(qt_randomdevice_control) & SkipHWRNG) == 0)
         filled += qt_random_cpu(buffer, count);
 
     if (filled != count && (uint(qt_randomdevice_control) & SkipSystemRNG) == 0) {
-        qssize_t bytesFilled =
-                fillBuffer(buffer + filled, (count - filled) * qssize_t(sizeof(*buffer)));
-        filled += bytesFilled / qssize_t(sizeof(*buffer));
+        qsizetype bytesFilled =
+                fillBuffer(buffer + filled, (count - filled) * qsizetype(sizeof(*buffer)));
+        filled += bytesFilled / qsizetype(sizeof(*buffer));
     }
     if (filled)
         fallback_update_seed(*buffer);
@@ -656,6 +656,11 @@ inline QRandomGenerator::SystemGenerator &QRandomGenerator::SystemGenerator::sel
  */
 
 /*!
+    \enum QRandomGenerator::System
+    \internal
+*/
+
+/*!
     \fn QRandomGenerator::QRandomGenerator(quint32 seedValue)
 
     Initializes this QRandomGenerator object with the value \a seedValue as
@@ -677,7 +682,7 @@ inline QRandomGenerator::SystemGenerator &QRandomGenerator::SystemGenerator::sel
  */
 
 /*!
-    \fn QRandomGenerator::QRandomGenerator(const quint32 *seedBuffer, qssize_t len)
+    \fn QRandomGenerator::QRandomGenerator(const quint32 *seedBuffer, qsizetype len)
     \overload
 
     Initializes this QRandomGenerator object with \a len values found in
@@ -694,7 +699,7 @@ inline QRandomGenerator::SystemGenerator &QRandomGenerator::SystemGenerator::sel
  */
 
 /*!
-    \fn QRandomGenerator::QRandomGenerator(const quint32 *begin, const quin32 *end)
+    \fn QRandomGenerator::QRandomGenerator(const quint32 *begin, const quint32 *end)
     \overload
 
     Initializes this QRandomGenerator object with the values found in the range
@@ -762,7 +767,7 @@ inline QRandomGenerator::SystemGenerator &QRandomGenerator::SystemGenerator::sel
 
     A typedef to the type that operator()() returns. That is, quint32.
 
-    \sa operator()()
+    \sa {QRandomGenerator::operator()}{operator()()}
  */
 
 /*!
@@ -774,6 +779,22 @@ inline QRandomGenerator::SystemGenerator &QRandomGenerator::SystemGenerator::sel
  */
 
 /*!
+    \fn quint32 QRandomGenerator::generate()
+
+    Generates a 32-bit random quantity and returns it.
+
+    \sa {QRandomGenerator::operator()}{operator()()}, generate64()
+ */
+
+/*!
+    \fn quint64 QRandomGenerator::generate64()
+
+    Generates a 64-bit random quantity and returns it.
+
+    \sa {QRandomGenerator::operator()}{operator()()}, generate()
+ */
+
+/*!
     \fn result_type QRandomGenerator::min()
 
     Returns the minimum value that QRandomGenerator may ever generate. That is, 0.
@@ -800,7 +821,7 @@ inline QRandomGenerator::SystemGenerator &QRandomGenerator::SystemGenerator::sel
     \fn void QRandomGenerator::seed(std::seed_seq &seed)
     \overload
 
-    Reseeds this object using the seed sequence \a sseq as the seed.
+    Reseeds this object using the seed sequence \a seed as the seed.
  */
 
 /*!
@@ -826,7 +847,7 @@ inline QRandomGenerator::SystemGenerator &QRandomGenerator::SystemGenerator::sel
     \endcode
 
     This function complies with the requirements for the function
-    \c{\l{http://en.cppreference.com/w/cpp/numeric/random/seed_seq/generate}{std::seed_seq::generate}},
+    \l{http://en.cppreference.com/w/cpp/numeric/random/seed_seq/generate}{\c std::seed_seq::generate},
     which requires unsigned 32-bit integer values.
 
     Note that if the [begin, end) range refers to an area that can store more
@@ -853,7 +874,7 @@ inline QRandomGenerator::SystemGenerator &QRandomGenerator::SystemGenerator::sel
  */
 
 /*!
-    \fn void QRandomGenerator::fillRange(UInt *buffer, qssize_t count)
+    \fn void QRandomGenerator::fillRange(UInt *buffer, qsizetype count)
 
     Generates \a count 32- or 64-bit quantities (depending on the type \c UInt)
     and stores them in the buffer pointed by \a buffer. This is the most
@@ -906,16 +927,16 @@ inline QRandomGenerator::SystemGenerator &QRandomGenerator::SystemGenerator::sel
     \endcode
 
     The same may also be obtained by using
-    \c{\l{http://en.cppreference.com/w/cpp/numeric/random/uniform_real_distribution}{std::uniform_real_distribution}}
+    \l{http://en.cppreference.com/w/cpp/numeric/random/uniform_real_distribution}{\c std::uniform_real_distribution}
     with parameters 0 and 1.
 
     \sa generate(), generate64(), bounded()
  */
 
 /*!
-    \fn qreal QRandomGenerator::bounded(qreal highest)
+    \fn double QRandomGenerator::bounded(double highest)
 
-    Generates one random qreal in the range between 0 (inclusive) and \a
+    Generates one random double in the range between 0 (inclusive) and \a
     highest (exclusive). This function is equivalent to and is implemented as:
 
     \code
@@ -931,7 +952,7 @@ inline QRandomGenerator::SystemGenerator &QRandomGenerator::SystemGenerator::sel
 
     Generates one random 32-bit quantity in the range between 0 (inclusive) and
     \a highest (exclusive). The same result may also be obtained by using
-    \c{\l{http://en.cppreference.com/w/cpp/numeric/random/uniform_int_distribution}{std::uniform_int_distribution}}
+    \l{http://en.cppreference.com/w/cpp/numeric/random/uniform_int_distribution}{\c std::uniform_int_distribution}
     with parameters 0 and \c{highest - 1}. That class can also be used to obtain
     quantities larger than 32 bits.
 
@@ -969,7 +990,7 @@ inline QRandomGenerator::SystemGenerator &QRandomGenerator::SystemGenerator::sel
 
     Generates one random 32-bit quantity in the range between \a lowest (inclusive)
     and \a highest (exclusive). The same result may also be obtained by using
-    \c{\l{http://en.cppreference.com/w/cpp/numeric/random/uniform_int_distribution}{std::uniform_int_distribution}}
+    \l{http://en.cppreference.com/w/cpp/numeric/random/uniform_int_distribution}{\c std::uniform_int_distribution}
     with parameters \a lowest and \c{\a highest - 1}. That class can also be used to
     obtain quantities larger than 32 bits.
 
@@ -1098,7 +1119,7 @@ inline QRandomGenerator::SystemGenerator &QRandomGenerator::SystemGenerator::sel
 
     A typedef to the type that operator()() returns. That is, quint64.
 
-    \sa operator()()
+    \sa {QRandomGenerator64::operator()}{operator()()}
  */
 
 /*!
@@ -1169,7 +1190,9 @@ QRandomGenerator64 QRandomGenerator64::securelySeeded()
     return result;
 }
 
-/// \internal
+/*!
+    \internal
+*/
 inline QRandomGenerator::QRandomGenerator(System)
     : type(SystemRNG)
 {
diff --git a/src/corelib/global/qrandom.h b/src/corelib/global/qrandom.h
index bde64646a4..46d3e0e152 100644
--- a/src/corelib/global/qrandom.h
+++ b/src/corelib/global/qrandom.h
@@ -44,6 +44,13 @@
 #include <algorithm>    // for std::generate
 #include <random>       // for std::mt19937
 
+#ifdef min
+#  undef min
+#endif
+#ifdef max
+#  undef max
+#endif
+
 QT_BEGIN_NAMESPACE
 
 class QRandomGenerator
@@ -55,10 +62,10 @@ public:
     QRandomGenerator(quint32 seedValue = 1)
         : QRandomGenerator(&seedValue, 1)
     {}
-    template <qssize_t N> QRandomGenerator(const quint32 (&seedBuffer)[N])
+    template <qsizetype N> QRandomGenerator(const quint32 (&seedBuffer)[N])
         : QRandomGenerator(seedBuffer, seedBuffer + N)
     {}
-    QRandomGenerator(const quint32 *seedBuffer, qssize_t len)
+    QRandomGenerator(const quint32 *seedBuffer, qsizetype len)
         : QRandomGenerator(seedBuffer, seedBuffer + len)
     {}
     Q_CORE_EXPORT QRandomGenerator(std::seed_seq &sseq) Q_DECL_NOTHROW;
@@ -131,7 +138,7 @@ public:
     }
 
     template <typename UInt, IfValidUInt<UInt> = true>
-    void fillRange(UInt *buffer, qssize_t count)
+    void fillRange(UInt *buffer, qsizetype count)
     {
         _fillRange(buffer, buffer + count);
     }
@@ -160,8 +167,8 @@ public:
     void seed(quint32 s = 1) { *this = { s }; }
     void seed(std::seed_seq &sseq) Q_DECL_NOTHROW { *this = { sseq }; }
     Q_CORE_EXPORT void discard(unsigned long long z);
-    static Q_DECL_CONSTEXPR result_type min() { return (std::numeric_limits<result_type>::min)(); }
-    static Q_DECL_CONSTEXPR result_type max() { return (std::numeric_limits<result_type>::max)(); }
+    static Q_DECL_CONSTEXPR result_type min() { return std::numeric_limits<result_type>::min(); }
+    static Q_DECL_CONSTEXPR result_type max() { return std::numeric_limits<result_type>::max(); }
 
     static inline Q_DECL_CONST_FUNCTION QRandomGenerator *system();
     static inline Q_DECL_CONST_FUNCTION QRandomGenerator *global();
@@ -177,7 +184,8 @@ private:
     friend class QRandomGenerator64;
     struct SystemGenerator;
     struct SystemAndGlobalGenerators;
-    typedef std::mt19937 RandomEngine;
+    using RandomEngine = std::mersenne_twister_engine<quint32,
+        32,624,397,31,0x9908b0df,11,0xffffffff,7,0x9d2c5680,15,0xefc60000,18,1812433253>;
 
     union Storage {
         uint dummy;
@@ -214,10 +222,10 @@ public:
     QRandomGenerator64(quint32 seedValue = 1)
         : QRandomGenerator(seedValue)
     {}
-    template <qssize_t N> QRandomGenerator64(const quint32 (&seedBuffer)[N])
+    template <qsizetype N> QRandomGenerator64(const quint32 (&seedBuffer)[N])
         : QRandomGenerator(seedBuffer)
     {}
-    QRandomGenerator64(const quint32 *seedBuffer, qssize_t len)
+    QRandomGenerator64(const quint32 *seedBuffer, qsizetype len)
         : QRandomGenerator(seedBuffer, len)
     {}
     QRandomGenerator64(std::seed_seq &sseq) Q_DECL_NOTHROW
@@ -235,8 +243,8 @@ public:
         QRandomGenerator::discard(z * 2);
     }
 
-    static Q_DECL_CONSTEXPR result_type min() { return (std::numeric_limits<result_type>::min)(); }
-    static Q_DECL_CONSTEXPR result_type max() { return (std::numeric_limits<result_type>::max)(); }
+    static Q_DECL_CONSTEXPR result_type min() { return std::numeric_limits<result_type>::min(); }
+    static Q_DECL_CONSTEXPR result_type max() { return std::numeric_limits<result_type>::max(); }
     static Q_DECL_CONST_FUNCTION Q_CORE_EXPORT QRandomGenerator64 *system();
     static Q_DECL_CONST_FUNCTION Q_CORE_EXPORT QRandomGenerator64 *global();
     static Q_CORE_EXPORT QRandomGenerator64 securelySeeded();